Method of cleaning refractory checkerwork in regenerative blast furnace stoves or the like



y 4. 1954 L. R. ROBINSON 2,677,628

METHOD OF CLEANING REFRACTORY CHECKERWORK IN REGENERATIVE BLAST FURNACE STOVES OR THE LIKE F'lled Nov. 17, 1951 2 Sheets-Sheet l HIHIIIIHIIHIIHI llll IHIHIIHIHIIH IIIIIH [III III! I HHH HIIIIIHII.

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1% 1 INVENTOR.

Lawrence R.Robinson 2 CUM ATTORNEYS y 4. 1954 R. ROBINSQN 2,677,628

METHOD OF CLEANING REFRACTORY CHECKERWORK IN REGENERATIVE BLAST FURNACE STOVE-5 OR THE LIKE Filed Nov. 17, 1951 2 Sheets-Sheet 2 mmvrox. Lawrence R.Robinson ATTORNEYS Patented May 4, 1954 UNITED STATES RATENT OFFICE METHOD OF CLEANING REFRACTORY CHECKERWORK IN REGENERATIVE BLAST FURNACE STOVES OR THE LIKE 4 Claims. 1

This invention relates to methods for cleaning refractory checkerwork, and, more particularly, is concerned with cleaning operations upon checkerwork in regenerative blast furnace stoves, and the like.

It has been proposed heretofore to clean refractory checkerwork, for example in blast furnace stoves, to improve the regenerative efficiency of these stoves. United States Patent No. 2,013,511 describes cleaning operations involving air or steam jets as being old, and then goes on to describe and claim a cleaning operation with water. It has been proposed to add an acid content to the water to further improve the cleaning action thereof.

However, the indicated patent teaches cleaning the refractory work from the top downwardly, and if any of the flues are semi or fully clogged, the cleaning becomes very difficult with the material that is cleaned from the flue depositing itself on the plugged portion of the flue, or else having to be washed clear up out of the top of the flue which is not only difficult but which causes the removed material to flow back into other flues.

In fact, flue cleaning as performed upon re fractory checkerwork heretofore has not been very successful and the cost has been high. It is often cheaper to tear out the old checkerwork and put in a new one than it is to satisfactorily and inexpensively clean the existing checkerwork. And if the checkerwork is not reasonably clean in a regenerative blast furnace stove, the emciency of the pre-heating operation performed by the stove falls oif very appreciably and to the point where the blast furnace requires a great deal more coke than i is the case when the air passed to the blast furnace is sufficiently pre-heated. The use of additional coke, of course, adds directly to the cost of the pig iron or hot metal produced by the blast furnace.

It is the general object of my invention to avoid and overcome the foregoing and other difficulties of and objections to prior art practices by the provision of an improved, simple, inexpensive, and readily performed method for rapidly and efliciently removing flue dust, such as iron oxide, silicon dioxide, and lime dust from refractory checkerwork in blast furnaces, stoves and the like.

Another object of my invention is to provide a method whereby the checkerwork can be cleaned from underneath'and progressively upwardly so that the removed dust falls directly to the floor of the stove from which it can be readily removed.

Another object of my invention is the provision of a cleaning method employinga flexible shaft or cable which is rotated with a cutting, probing or cleaning tool on its end and to thereby positively and mechanically unplug and thoroughly clean all lines in a regenerative stove.

Another object of my invention is to provide a cleaning method of the character described wherein the cleaning of the lines is initiated in a progressively upward manner from underneath the flues, and the flues are finished after the stove has cooled by men working from above, so that the overall time that a stove is down i reduced to a minimum.

Another object of my invention is to provide an improved cleaning method of employing a flexible rotary cable whereina cutting or cleaning tool is positioned on each end of the flexible cable and the cleaning tools are put in separate flues so that as one cable end and tool are being removed from one flue; the'other cable end and cleaning tool are being moved into a second flue, with this operation being repeated until the entire checkerwork is cleaned.

The foregoing objects of my invention, and other object which will become apparent as the description proceeds, are achieved by a refractory checkerwork cleaning method comprising the steps of isolating the checkerwork, mechanically removing dust and deposits from the flues from the lower end of the fines progressively upwardly so that the dust and deposits progressively fall through the cleaned portion of the fines to the floor of the stove. The mechanical removing operation is usually performed with an upwardly 'directed rotating flexible cable carrying a cleaning tool. The entire cleaning operation can be in the progressive upward manner described, but the invention particularly contemplates reducing the overall elapsed cleaning time by completing the cleaning of the top of the lines from the top downwardly by mechanically removing dust and deposits from the lines progressively downwardly with the removed material falling through the previously cleaned and opened lower portions of the dues to the floor of the stove. The invention also utilizes the idea of having a cleaning tool upon each end of the flexible shaft or cable with the one cable end and cleaning tool being progressively removed from a flue while the other end of the cable and the second cleaning tool are progressively advanced into another flue. This operation when continuously repeated substantially doubles the-production capacity of the mechanical equipmentand of the cleaning method.

.For a better understanding of my invention,

reference should be had to the accompanying drawings wherein:

Fig. l is a vertical sectional view of a typical blast furnace regenerative stove and illustrating the refractory checkerwork thereof;

Fig. 2 is a horizontal cross-sectional view, taken on line II II of- Fig. 1, and illustrating a typical polygonal checkerwork;

Figs. 3 and 4 are views similar to Fig. 2, but illustrating, respectively, a center combustion stove, and a side combustion stove having a basket weave type of checkerwork; and

Fig. 5 is a view similar to Fig. 1, and illustrating the step of completing the cleaning of the flues of the stove from above.

It will be appreciated that the principles of my invention can be utilized for'the cleaning of refractory cheokerwork of various types and kinds, but a particularly important application of my invention is with respect to blast furnace stoves, and the invention has been so illustrated and will be so described. The operation of a regenerative stove for blast furnace use is so well known as to warrant no detailed description. Suflice it to say that usually three or four stoves are positioned adjacent a blast furnace, with several of the stoves being heated by the blast furnace gas, usually high in carbon monoxide, escaping from the top of the blast furnace.

The stove or stoves not being heated, but which 5 have previously been heated by the blast furnace gas are used for pre-heating the air passing to the blast furnace tuyeres. Every several hours the cycle is reversed so that the heated stoves are used to pre-heat the air, or as the blast furnace man calls it, the wind, passing to the blast furnace, and the stove or stoves previously used to pre-heat the wind are brought back up to a high temperature by burning the blast furnace gas therein.

As is well known, blast furnace stoves can be of a variety of types and shapes, and can include checkerwork of various types defining flues of a variety of sizes. I have found that the principles of my invention can be utilized to clean, substantially all types and sizes of checkerwork.

Having reference to the drawings, the numeral l0 indicates generally a regenerative stove having a side combustion chamber [2, a dome top I, M, an arched bottom chamber l6, and the usual openings 18, 20, and 22 for controlling the flow ofeither wind or blast furnace gas'in accord with known regenerative techniques. Within the stove I0 is the refractory checkerwork 24, and

this checkerwork has been shown in Fig. 2 to weave checkerwork of Figs. 3 and 4., provide flue 7 openings which normally range from about four by four inches up to about four and one-half inches by nine inches. In the checkerwork 24 of Fig. 2, which can bemade hexagonal, octagonal, or circular, the flue size may,- vary, from an, inch and one-half internal diameter up to about six inches internal diameter.

As particularly illustrated in Fig. 1 of the drawings, in the practice of my invention the stove I0 is first isolated, and as soon as it is sufiiciently cooled a man 30 enters the chamber 16 underneath the checkerwork 24 and directs a flexible cable or shaft 32 with a cleaning or cutting tool 34 thereon upwardly into one of the flue openings. The flexible shaft 32 extends laterally out of the opening 22 in the stove and through a driven rotary chuck mechanism 36 positioned in front of the opening 22. The mechanism 36 is normally moved toward the stove l9. tov advance the flexible shaft 32 and cleaning tool 34 upwardly into the flue. When the rotary chuck mechanism 36 is moved close to the stove it is stopped, new lengths of flexible shaft 32a are added to the shaft 32, the chuck mechanism 36 is released and is moved backwardly over the new shaft 32a, the chuck is reengaged and the flexible shaft is again rotated and the mechanism 36 is moved toward the stove H). This operation is repeated until the desired cleaning operation on a particular flue is completed.

l-he flexible shaft is then backed out of the cleaned flue and the operation is repeated on the next flue to be cleaned. In this second and in subsequent cleaning operations, the flexible shaft is usually left assembled in one piece, but withinthe discretion of the operator and as perhaps determined by the conditions surrounding the stove, the shaft can be disassembled if desired. Or the operator can employ the simultaneous in and out, or double ended cable and tool method hereinafter described.

It will be recognized that in the operation as described that the fines are cleaned from the bottom in a progressively upward manner, and with all dust and deposits in the flue readily dropping downwardly through the already cleaned flue portion to the floor of the stove ID from which the dust and deposits can be readily removed, for example, by'shovel and wheel barrow. The operation as described is repeated with respect to the various other fiues in the stove until the desired cleaning operation is completed.

The method as just described has several distinct and important advantages. The dust and deposits in the flues are positively and mechanically removed, and are removed in a manner so that they do not tend to further clog the lines, as is the case when the flues are cleaned from the top downward. Also, with my improved method as described, I am able to enter a stove and to commence the cleaning thereof at a time much earlier than is possible when the stove is cleaned from the top. This is because an indraft of cool air through the opening 22 can be readily established to cool the men in my cleaning operation, with the cool air being drawn passed the men and upwardly through the checkerwork 24 by the normal draft creating char- 1 actcristics of the still hot checkerwork 24, with this flow of air being discharged usually through the dome M of the stove. This draft of cool air-can be supplemented with power driven cool air blowers if desired.

Thus, men can enter the stove to perform my improved cleaning operation at a time considerably. in advance of the time that they can get on top of the checkerwork. 24, for. example, with the top of the stove still at a temperature of between-100? and.800, and theresult is that the stove is out of operation a definitely shorter time than is the case with former cleaning methods.

Sometimes I perform my entire cleaning operation from the bottom of the stove in the manner just described. However, it is part of my inventive concept to further reduce the overall time that the stove is out of operation by a combination of bottom and top flue cleaning. This I achieve by first cleaning the fiues in an upward direction and finishing the cleanin of the flues from the top downwardly. The fiues are generally dirtiest and most glazed at the top where the hot gas from the blast furnace first strikes the checkerwork, so that the final or finishing cleaning operation from the top of the stove is often desirable.

In Fig. 5 I have illustrated cleaning the lines from the top downwardly, and in this figure of the drawings, the men 33 have gone into the dome His 01 the stove its and are standing with the drive mechanism 36a on top of the checkerwork Ed. The flexible shaft or cable 322) is provided with. cleaning implements Ma and 341) at each end, as the cleaning implement 34a is removed upwardly out of a flue in the checkerwork 2 the cleaning tool 341; is advanced downwardly into a previously uncleaned flue. Then as the tool 3% is moved back out of the flue it has cleaned, the cleanin tool t la is put into another fiue and it cleans downwardly into this flue. This alternate in and out or double ended cable and tool operation is continuously repeated until all of the flues have been cleaned from the top downwardly the desired distance.

It shoulde be understood that in performing my improved cleaning process that a single crew of men can first clean the lines upwardly from the bottom in the manner described and that by this time the checkerwork has ordinarily cooled to a point where the crew can then get into the dome of the stove to complete the cleanin of the lines from the top downwardly in the manner just described in conjunction with Fig. 5.

I also contemplate that if th temperature conditions of the checkerwork 24 are such as to allow both a top and a bottom crew to work simultaneously upon a stove that the top and bottom cleaning operation described can be performed simultaneously. It should be noted, also, that the alternate in and out or double ended cleaning operation as described in conjunction with Fig. 5 may sometimes be utilized to clean the lines from the bottom in a progressively upward manner as Well as being used to clean the fines downwardly from the top of the checkerwork.

From the foregoin it will be recognized that the various objects of my invention have been achieved by the provision of an improved refractory checkerworl: cleaning method whereby the fines thereof are positively and efficiently cleaned at a minimum of expense and in a minimum of time so as to restore the checkerwork, as in a regenerative stove for blast furnace use, to substantially original efficiency.

The term flexible cable or flexible shaft, as employed throughout the specification and claims, is intended to include either a closely coiled helical wire forming a flexible cable, or a flexible rod or rods, usually between about A," and about in diameter, or stiif rods connected with universal joints, although this last structure is not recommended.

While in accord with the patent statutes, I have illustrated and described certain best known em- 6 l bodiments of my invention in detail, and it is to be particularly understood that I am not to be limited thereto or thereby, and that the scope of my invention is defined in the appended claims.

I claim:

1. That method of cleaning refractory checkerwork in a regenerative blast furnace stove, or the like, comprising isolating the stove while still hot from the regenerative operation, establishing a flow of cool air, by the stack draft characteristics of the hot checkerwork, into the bottom of the stove and upwardly through the hot checkerwork, standing in the flow of cool air adjacent the bottom of the hot stove and mechanically removing with a rotary motion dust and deposits from the checkerwork flues from the lower end thereof progressively upwardly so that the dust and deposits progressively fall through the cleaned portion of the flues to the floor of the stove, and removin the fallen dust and deposits from the floor of the stove.

2. That method of cleaning refractory checkerwork in a regenerative blast furnace stove, or the like, comprising isolating the stove while still hot from the regenerative operation, establishing a flow of cool air, by the stack draft characteristics of the hot checkwork, into the bottom of the stove and upwardly through the hot checkerwork, standing in the flow of cool air adjacent the bottom of the hot stove and mechanically removing with a rotary motion dust and deposits from the checkerwork flues from the lower end thereof progressively upwardly so that the dust and deposits progressively fall through the cleaned portion of the fiues to the floor of the stove, the aforesaid cleaning operation terminating short of the top of the flues, then cleaning the top of the fines from the top downwardly by mechanically removing with a rotary motion dust and deposits from the fiues progressively downwardly with the removed material falling through the previously cleaned lower portions of the fiues to the floor of the stove, and removing the fallen dust and deposits-from the floor of the stove.

3. That method of cleaning refractory checkerwork in a regenerative blast furnace stove, or the like, comprising isolating the stove while still hot from the regenerative operation,

- establishing a flow of cool air, by the stack draft characteristics of the hot checkerwork, into the bottom of the stove and upwardly through the hot checkerwork, standing in the flow of cool air adjacent the bottom of the hot stove, introducing a flexible cable with a flue cleaning tool adjacent one end into the lower end of a flue, rotating the cable and tool with the other end of the cable extending outside of the stove, advancing the cable and tool into the flue as it is rotated to mechanically and progressively remove the dust and deposits from the flue, and until the other end of the cable is inside the stove, stopping the rotation of the cable, attaching a second flue cleaning tool to the said other end of the cable, introducing said second tool into a second flue, commencing the rotation of the cable, progressively removing the cable and first tool from the cleaned flue and simultaneously progressively advancing the second tool and other end of the cable into the second flue to clean it, and repeating this simultaneous in and out movement of the tools and the associated repositioning of one of the tools in turn in an uncleaned flue until substantially all fiues are cleaned.

4. That method of cleaning refractory cheokerwork in a regenerative blast furnace stove, or the like, comprising isolating the stove while still hot from the regenerative operation, establishing a flow of cool air into the bottom of the stove and upwardly through thehot checker- Work, standing in-the flow of cool air and mechanically removing with a rotary motion dust and deposits from the checkerwork' fiues from the lower end-thereof progressively upwardly so that the dust and deposits progressively fall through the cleaned portion of the fiues to the fioor of the stove, and removing the fallen dust anddeposits from the fioor of the stove.

References-Cited in the-file of this patent- Number Number UNITED STATES PATENTS Name Date Forsyth Nov. 28, 1899 Schilow Nov. 19, 1912 Fletcher July 10,1928 Steinbacher Sept. 3, 1935 Weir Apr. 24, 1945 Peters Mar. 29, 1949 FOREIGN PATENTS Country Date Great Britain of 1905 

1. THAT METHOD OF CLEANING REFRACTORY CHECKERWORK IN A REGENERATIVE BLAST FURNACE STOVE, OR THE LIKE, COMPRISING ISOLATING THE STOVE WHILE STILL HOT FROM THE REGENERATIVE OPERATION, ESTABLISHING A FLOW OF COOL AIR, BY THE STACK DRAFT CHARACTERISTICS OF THE HOT CHECKERWORK, INTO THE BOTTOM OF THE STOVE AND UPWARDLY THROUGH THE HOT CHECKERWORK, STANDING IN THE FLOW OF COOL AIR ADJACENT THE BOTTOM OF THE HOT STOVE AND MECHANICALLY REMOVING WITH A ROTARY MOTION DUST AND DEPOSITS FROM THE CHECKERWORK FLUES FROM THE LOWER END THEREOF PROGRESSIVELY UPWARDLY SO THAT THE DUST AND DEPOSITS PROGRESSIVELY FALL THROUGH THE CLEANED PORTION OF THE FLUES TO THE FLOOR OF THE 